"Scientific American popular science supplement, No. 799, April 25, 1891" is a publication that is closely related to the development of science and technology at the end of the XIX century. In this issue, readers will be able to learn about the latest achievements in the world of science, discoveries and inventions of that time. The authors share interesting facts, leading trends and perspectives of science and technology without pretensions. This book will be a useful resource for anyone who is interested in the history of scientific discoveries and wants to gain a deeper understanding of the essence and meaning of scientific progress.